Correlation of Himalayan exhumation rates and Asian monsoon intensity

Abstract

Although most data suggest that the India-Eurasia continental collision began 45-55 Myr ago, the architecture of the Himalayan-Tibetan orogen is dominated by deformational structures developed in the Neogene period (<23 Myr ago). The stratigraphic record and thermochronometric data indicate that erosion of the Himalaya intensified as this constructional phase began and reached a peak around 15 Myr ago. It remained high until 10.5 Myr ago and subsequently slowed gradually to 3.5 Myr ago, but then began to increase once again in the Late Pliocene and Pleistocene epochs. Here we present weathering records from the South China Sea, Bay of Bengal and Arabian Sea that permit Asian monsoon climate to be reconstructed back to the earliest Neogene. These indicate a correlation between the rate of Himalayan exhumation as inferred from published thermochronometric data and monsoon intensity over the past 23 Myr. We interpret this correlation as indicating dynamic coupling between Neogene climate and both erosion and deformation in the Himalaya. Show more